The coercivity mechanism of Nd-Fe-B based magnets prepared by a new technique of strip casting was investi-gated. Different from the traditional magnets, α-Fe phases are difficult to be found in Nd-Fe-B magnets prepared by stripcasting. Meanwhile, the rich-Nd phases occur not only near the grain boundaries of main phases, but also within themain-phase grains. Investigation on the magnetizing field dependence of the coercivity for the(Nd_(0.935)Dy_(0.065))_14.5Fe_(79.4)B_(6.1)magnet and the temperature dependence of the coercivity for the Nd_(14.5)Fe_(79.4)B_(6.1) magnet havebeen done. Results show that coercivities for strip casting magnets are controlled by the nucleation mechanism. The coercivity mechanism of Nd-Fe-B based magnets prepared by a new technique of strip casting was investi-gated. Different from the traditional magnets, α-Fe phases are difficult to be found in Nd-Fe-B magnets prepared by stripcasting. Investigation on the magnetizing field dependence of the coercivity for the (Nd_ (0.935) Dy_ (0.065)) _14.5 Fe_ (79.4) B_ (6.1) magnet and the temperature dependence of the coercivity for the Nd_ (14.5) Fe_ (79.4) B_ (6.1) magnet havebeen done. Results show that coercivities for strip casting magnets are controlled by the nucleation mechanism.